Results:

EGCG and curcumin at 10 μM concentration reversed EMT, inhibited proliferation and migration through Smad-3 phosphorylation, when induced by TGF-β1 in ARPE-19 cells. Lycopene did not prevent EMT in ARPE-19 cells.

Interpretation & conclusions:

EGCG and curcumin are potent in preventing EMT induced by TGF-β1 in ARPE-19 cells and therefore, proposed as potential molecules for further pre-clinical evaluation in PVR management.

Effect of EGCG, curcumin and lycopene on expression of vimentin, α-SMA and ZO-1: ARPE-19 cells treated with TGF-β1 or co-treated with indicated concentration of EGCG, curcumin or lycopene for 48 h and stained for α-SMA, vimentin and ZO-1 (green fluorescence) and nucleus was stained with DAPI (blue fluorescence). All the images were taken using Carl-Zeiss fluorescence microscope (×40).

Effect of EGCG, curcumin and lycopene on proliferation of ARPE-19 cells. MTT assay was done after treating ARPE-19 cells with TGF-β1 and co-treated with EGCG, curcumin or lycopene for 48 h. The bar graph represents per cent proliferation of cells as normalized to control. Data represent mean±standard deviaton of three independent experiments in triplicates. ***P<0.001 compared to control, ###P<0.001 compared to TGF-β1. MTT, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide.

Effect of EGCG, curcumin and lycopene on migration of ARPE-19 cells. Representative images showing scratch assay on ARPE-19 cells, treated with TGF-β1 alone or co-treated with various concentrations of EGCG, curcumin and lycopene. Cells were imaged immediately after the scratch was made i.e. at 0 h and 36 h after the scratch (×4).

Effect of EGCG, curcumin and lycopene on Smad-3 phosphorylation: (A) EGCG, curcumin and not lycopene reduced the phosphorylation of Smad-3 induced by TGF-β1 in ARPE-19 cells. (B) Densitometry is represented as bar graph. Data represent mean±standard deviation of three independent experiments in triplicates.*P<0.05 compared to control, #P<0.05 compared to TGF-β1.